Mesenchymal stromal cells as a resource for regeneration of damaged skin

Skin lesions, particularly chronic nonhealing wounds, represent an important medical problem. Mesenchymalstromal cells (MSCs) are a promising source for the cell therapy of skin defects, because they can stimulate regeneration, largely by the paracrine production of cytokines, chemoattractants, and growth factors. MSCs are involved in all stages of the wound-healing process, since they are a universal regulator of the regeneration process. These cells improve the course of inflammation, stimulate the proliferation of epithelium and fibroblasts, promote angiogenesis, and prevent excessive scarring. The results of numerous preclinical studies suggest that the effect of MSCs on skin repair is beneficial. This review considers the mechanisms of MSC participation in the skin-wound healing; clinically relevant sources of these cells; methods of their delivery into the wound; means of enhancing their therapeutic efficiency; the possible application of MSC secretory products; and the mobilization of endogenous MSCs from the bone marrow into the wound. Promising approaches of MSC use for impaired regeneration due to diabetes and irradiation are also reviewed.